THE QUANTUM YIELD OF THE PHOTO-DECOMPOSITION OF SOME AROMATIC DIAZONIUM SALTS

• Document Type: CREST
• Collection: General CIA Records
• Document Number (FOIA) /ESDN (CREST): CIA-RDP83-00423R002000130005-0
• Release Decision: RIPPUB
• Original Classification: K
• Document Page Count: 8
• Document Creation Date: November 9, 2016
• Document Release Date: February 22, 1999
• Sequence Number: 5
• Publication Date: August 1, 1952
• Content Type: REPORT

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SEPARAAT
2053
LABORATORIIA
N.V. PHILIPS' GLOEILAMPENFABRIEKEN
EINDHOVEN (HOLLAND)
THE QUANTUM YIELD OF THE PHOTO-
DECOMPOSITION OF SOME AROMATIC
DIAZONIUM SALTS
J. de JONGE, R. DIJKSTRA and G. L. WIGGERINK
GEPUBLICEERD IN: RECUEIL DES TRAVAUX CHIMIQUES DES PAYS BAS 71,
846-852, AUGUSTUS 1952
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RECLIEIL DES TRAVAUX CHIMIQUES DES PAYS-PAS
pub). par la Soc. chim. neerl. ['s-Gravenhage (Hollande), Lange Voorhout 5]
T. 71, 8 (aout 1952).
Soc, anon. d'editions scientifiques. D. B. CENNTEN, Amsterdam.
547.556.7 : 541,14.8
THE QUANTUM YIELD OF THE PHOTO-DECOMPOSITION
OF SOME AROMATIC DIAZONIUM SALTS
J. DE JONGE, R. DIJKSTRA and G. L. WIGGERINK
(Philips Research Laboratories, N.V. Philips' Gloeilampenfabrieken,
Eindhoven - Netherlands).
The quantum yield of the photo-decomposition of some aromatic
diazonium salts in solution is estimated, using light with a wavelength of
3650 A. - .
The photo-decomposition of phenyl-amino benzene diazonium sulphate is
proposed as a suitable actinometer.
The quantum yield of the photochemical isomerisation of stable
p-methoxy-benzenediazo-cyanide was found to be about 0.35.
Many aromatic diazonium salts are photo-sensitive. The action of
light of suitable wavelength, e.g. 3500-4000 A, generally leads to a
decomposition into the corresponding phenol together with generation
of nitrogen
light
R-N2CI -,- H2O -> ROH + N2 + HCI
If a hydroxy-group is present in the aromatic nucleus in o-position
to 'the diazonium group (o-hydroxy:diazonium compounds, o-diazo-
oxides) the photo-decomposition product is a derivative of cyclopenta-
diene or indene carboxylic acid 1).
light i / II 1CO2H
+ 0i-) H2O --r ~ + + N
2
Generally, the decomposition of diazonium salts in acidic aqueous
solution may be a carbonium-ion reaction. In the case of the
o-hydroxy-diazonium compounds a re-arrangement takes place in the
transient, carbor;ium-ion 2).
Under suitable conditions there are no side reactions since prolonged
1) O. Sus, Ann. 556, 65, 85 (1944) ; J. de Jonge and R. Dykstra, Rec, tray. chim.
67, 328 (1948).
?) J. de Jonge and R. Dykstra, Rec. tray. chim. 69, 1448 (1950).
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847 J. de Jorge, R. DUkstra and G. L. Wiggerink,
irradiation of diazonium salts may lead to a complete decomposition
accompanied by the generation of nitrogen to almost the theoretical
amount obtainable 3).
The present paper deals with the determination of the quantum
efficiency of this photochemical decomposition in aqueous solution,
which may be found from the amount of diazonium compound
decomposed after absorption of a known nuriiber of light quanta.
A suitable measure for the photochemical effect is the volume of
generated nitrogen or the decrease in the concentration of diazonium
salt. The latter decrease may be calculated from the light absorption
of the solution before and after exposure.
Experimental values for the quantum yield qp have hitherto been
reported only for two diazonium salts.
Nz(+)
pc-) H3O(+)
SOS{-)
For phenyl-amino-benzene diazonium sulphate (1) in aqueous solu-
tion Schrdter a) found p = 0.20 when irradiating with light of 3650 A.
The volume of generated nitrogen was measured as a displacement of
a drop of toluene in a capillary tube mounted horizontally. With the
light absorption method a value of (y = 0.63 was found, while 0roodeve
and Wood 5) reported qp = 0.34.
Schrdter measured a quantum yield q = 0.34 for 2-naphthol-dia-
zonium-4-sulphonic acid (II) using the nitrogen method and irra-
diation with light of 3650 A. Using the light absorption method the
same aut)ior reported p = 0.58. while Fukushima 6) found a much
lower value, viz. p = 0.16,
These data appear to be rather scattering.
Here a report is given on the determination of the quantum yield
of further diazonium salts, including the two compounds mentioned
above, taking the volume of generated nitrogen as a measure for the
degree of decomposition.
The solutions of the diazonium salts containing 0.001-0.004 mole
6) J. S. Schmidt and W. Maier, Ber. 64, 778 (1931); G. Spencer and T. J. Taylor,
Chemistry 1' Industry 22, 308 (1947). See also the experimental part of this paper.
4) W. Schrdter, Z. w.. Phot. 28, 1 (1930).
6) C. P. Goodeve and L. J. Wood, Proc. Roy. Soc. A 166, 342 (1938).
6) 1. Pukushima and M. Florio, Mem. Coll. Eng. Kyoto Imp. Univ. 6, 184
(1930/31).
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The quantum yield of the photo-decomposition, etc. 71 (1952) RECUEIL 848
per litre were exposed in a closed cell to the radiation of a high-
pressure mercury lamp provided with a Wood filter. The light source,
giving almost monochromatic light of 3650 A, was calibrated by
means of a thermopile and'with the uranyl-oxalate actinometer.
All the light falling on the cell was absorbed by the solution. The
nitrogen produced was collected in a 2 ml nitrometer with the aid of
a slow current of pure carbon dioxide.
A schematical diagram of the apparatus is given in figure I. Further
details of the procedure are to be found in the experimental part.
.capillary tube 34mm
The, results have been tabulated in the table on the next page.
Unless otherwise mentioned the diazonium salts were `irradiated in
aqueous solution. For the compounds III and V, being practically
insoluble in water, 20 % and 40 % aqueous ethanol was chosen as a
solvent.
The quantum yields of the diazonium salts investigated vary from
0.20 to 0.74. Our figure for phenyl-aminobenzene diazonium sulphate
is in complete agreement with the result of Goodeve and Wood. The
yield for diazonaphthol -1,2 (III) is found to approximate closely that
of its sulphonic acid (II). A quantum yield cp = 0.47 is found both
for the p-hydroxybenzene-diazonium salt (IV) and for the o-hydroxy-
benzene-diazonium compound (VI).
The photo-decomposition of diazonium salts for actinometric pur-
poses.
The generation of a known amount of nitrogen after irradiating of,
e.g., phenyl-aminobenzene-diazonium sulphate with ultraviolet light
(3650 A) may be used as a suitable actinometer. The value = 0.35
for the quantum yield may be taken. Another suitable diazonium salt
is naphthol-diazonium-sulphonic acid (II) with